Not until 1992, just after the Soviet Union was dissolved, did
additional material about this episode emerge. A historical-archival
journal, Istoricheskii arkhiv (Historical Archive), which had
been published in the USSR from 1955 until 1962, began appearing again
in 1992 with transcriptions of declassified documents from the former
Soviet archives. The first issue of the revived Istoricheskii arkhiv
in 1992 contained a section about the transfer of Crimea that featured
documents from the Russian Presidential Archive and from a few other
archives whose collections are now housed at the State Archive of the
Russian Federation (GARF). Unfortunately, these documents do not add
anything of substance to what was published in the Soviet press 38 years
earlier; indeed, they are mostly identical to what was published in
1954. (Apparently, the editors of Istoricheskii arkhiv were unaware that the scripted proceedings of the USSR Supreme Soviet Presidium meeting
had already been published in 1954.) The documents do confirm that the
move was originally approved by the Presidium of the Communist Party of
the Soviet Union (CPSU) on 25 January 1954, paving the way for the
authorizing resolution of the Presidium of the USSR Supreme Soviet three
weeks later. But the declassified files reveal nothing more about the
motives for the transfer, leaving us with just the two official
rationales that were published in 1954:

Neither of these ostensible justifications holds up to scrutiny. Even though 1954 was the 300th
anniversary of the Treaty of Pereyaslav, there is no connection between
that treaty and the Crimean peninsula. Pereyaslav, in central Ukraine
not far from Kyiv, is nowhere near Crimea, and the treaty had nothing to
do with the peninsula, which did not come under Russian control until
130 years later. Moreover, the description of the treaty as having
produced the “unification of Russia and Ukraine” is hyperbolic. The
treaty did provide an important step in that direction, but years of
further struggling and warfare had to take place before full unification
occurred. In retrospect the Treaty of Pereyaslav is often associated
(inaccurately) with Russian-Ukrainian unity, but it is hard to see why
anyone in the USSR would have proposed celebrating the 300th anniversary of the document by transferring Crimea from the RSFSR to the UkrSSR....